Recommended lens for copying prints

[Millie]

I'm looking to convert a friends watercolour prints into digital files so that he can reproduce then either as prints or postcards. I'm not sure of the legal implications but that will be another subject matter.

I'd like recommendations for a suitable lens. I currently use a Canon 350D so it would have to be a Canon fit. I've been told I should get a 1:1 Macro lens to reduce barrelling so confirmation of that would be appreciated. The prints would be anything up to A3 size so I'm not sure about focal length. I'd preferably like to use a camera stand as opposed to a tripod so if anyone out there has done a similar task any recommendations on the support would also be appreciated.

My thanks in advance.

[FUJI]

Hi, Millie,

Welcome to TIPF.

THIS MAY HELP YOU?

http://www.guildsourcebooks.com/pdf/sourcebook/howto_photograph_artwork.pdf

FUJI

[Millie]

That's a great starter for ten thanks Fuji

[Guest DaveW]

For copying flat items you need a lens with a flat field, which usually means a proper macro lens. Not a telephoto zoom with a so called macro facility since that is simply a closer focusing facility on a normal telephoto zoom which is unlikely to be corrected for a flat field. As a Canon user this link may be helpful:-

http://www.bobatkins...cro_lenses.html

Obviously for your purpose you do not need to get into the macro zone, but you do need flat field lenses so the image of your friends prints is sharp from edge to edge. As to some recommending using a telephoto, that would simply mean a longer focal length macro lens in the 135mm - 180mm range, rather than the shorter 55mm - 60mm range, so you could photograph from further back to avoid distortion.

In addition to Fuji's link you may find these helpful:-

http://www.betterpho...icle.asp?id=170

http://mgreerphoto.b...ph-artwork.html

Extensive article here on all forms of photographing art:-

http://www.dallasart...Photo-Art.shtml

DaveW

Edited October 23, 2012 by DaveW

[Millie]

Dave - thanks those are some really useful websites you've recommended there.

Can I just ask what you mean by a 'flat' lens?

Cheers

[Guest DaveW]

Hi Millie,

Feel free to ask anything you want. We may not know the answers, but can always try and find them!

A lens having Flatness of Field (not a "flat" lens) means the ability of the lens to exactly focus both the centre and the edges of a flat object onto the sensor. In normal photography you seldom focus flat objects exactly parallel to the sensor so you do not notice slight curvature of field, but if photographing flat art work you may notice that the edges of the image are not as sharp as the centre if the lens has significant curvature of field. This link, particularly the diagram by Bob Blakley, if you scroll down explains it:-

http://photo.net/lei...rs-forum/00Jhhj

Also here:-

http://www.flickr.co...ill/7249341446/

Lenses generally want to project their focused image onto a curved surface rather than a flat sensor. In humans our eyes have solved this by having a spherically curved retina. However it was impossible to make curved film to go through a camera and still too expensive to make curved sensors (though I think it has been tried) so they have to try and make lenses focus on a flat one. Correcting them perfectly costs money, which is why with things like zooms and normal lenses they do not do it completely, only bothering for specialist lenses like macro lenses where they will be used for photographing flat objects for copying etc.

A way to see if a lens is suitable for flat copying is to pin a sheet of newspaper perfectly flat and full of text onto a wall. Line the camera up with it's height at the papers centre and perfectly parallel horizontally and vertically to it. Take a couple of pictures and blow them up larger and see if the text is equally sharp both in the centre and edges of the image, or pretty well so since all lenses may have a slight field curvature, but in a macro lens it should be minimal. Usually fixed focal length lenses are best for having a flat field since they were easier to correct for the designer. As soon as you try and make a lens do many more things, like zoom and change it's focal length for instance, you have to compromise to get reasonable optical quality throughout it's range rather than better quality at a fixed focal length, which is why proper macro lenses are of fixed focal lengths not zooms.

Hope that explains it?

DaveW

Edited October 25, 2012 by DaveW